A. Field of the Invention
The present invention relates generally to the field of measuring microscopes, and more particularly to a protraction device for measuring microscopes having a rotatable reticle connected to an angle encoder for measurement of angles.
B. Description of the Prior Art
Measuring microscopes are used mainly for two-dimensional measurements, usually of a distance between two points on a microscopic object. However, measurement of an angle associated with a microscopic object is often of great importance. Heretofore, angular measurements have been made possible by removal of a microscope binotube and installation of a rotatable eyepiece having a specially marked reticle. Another well-known design for angular measurement includes an enlarged rotatable reticle disc having angle markings at a radially outer portion thereof which may be viewed by a user with the help of a magnifying glass. A further prior art protraction device comprises a permanently mounted rotatable reticle and means for selectively reflecting an image of the reticle into the eyepiece.